JP5341770B2 - Polypropylene blown film - Google Patents

Description

The present invention relates to polypropylene, more particularly mainly blown film.
The present invention relates to polypropylene useful for use in the manufacture of film).

  The film market requires polypropylene resins that can provide a special combination of film properties. Typically, cast, double bubble (tubular) and water quenched blown film processing can be used to produce polypropylene films with high transparency and high gloss values. Also, optically excellent film characteristics can be obtained by biaxial orientation (BOPP) by tender-frame processing. If an ordinary polypropylene resin is used in the process of air-cooled blown film widely used in the production of polyethylene film, a film showing high transparency cannot be produced.

  It would be desirable to achieve a highly transparent and high gloss inflation film made of polypropylene using existing processing techniques. It is also desired to produce an inflation film that exhibits high tensile stress.

Summary In one embodiment, the present invention includes an inflation film comprising polypropylene, wherein the polypropylene exhibits a melt flow rate of 1.8 g / 10 min to 14.0 g / 10 min and a melting point of at least 115 ° C. and The blown film exhibits a haze value of less than 10% and a gloss value of 70% or more.

  In one aspect, the present invention includes a product, the product comprising an overlap for retail clothing, a special bread film, a pouch for fresh cut products, a vertical bag filling and packaging for cereals (eg rice and beans). Materials, heat-resistant films, sealant webs, frozen food films that reduce the degree of unauthorized use, or products as minor components that can be included in shrink films.

  In one embodiment, the present invention comprises polypropylene having a melt flow rate of 1.8 g / 10 min to 14.0 g / 10 min and a melting point of at least 115 ° C. and having a haze value of less than 10% and 70% or more A method of forming an inflation film exhibiting a gloss value of, comprising: quenching the inflation film with air having a temperature of less than 10 ° C. and further comprising internal bubble cooling, external bubble stabilization And dual lip air rings.

FIG. 1 illustrates gloss values and haze values exhibited by blown structures formed from a clarified polymer. FIG. 2 illustrates gloss values and haze values exhibited by an inflation structure formed from a polymer produced using a metallocene catalyst. FIG. 3 illustrates the secant modulus and haze / tensile stress ratio exhibited by the film. FIG. 4 illustrates tear resistance and dart impact resistance.

Detailed Description Introduction and Definitions A detailed description is provided here. Each of the appended claims defines an individual invention, which is recognized to include equivalents of the various elements or constraints set forth in the claims for purposes of conflict. When referring to the “invention” below, they may all refer to certain specific embodiments, depending on the circumstances. It will be appreciated that references to “invention” in other cases refer to subject matter recited in one or more, but not necessarily all, of the claims. Here, each of the inventions including specific aspects, modifications and examples will be described in more detail below, but the present invention is not limited to such aspects, modifications and examples, and It is intended to enable those skilled in the art to make and use the invention when combined with the information and techniques available in this patent.

  Various terms as used herein are listed below. If a term used in a claim is not defined below, to the extent it is the broadest definition given to the term by an engineer in the relevant technical field, as indicated in printed publications and issued patents. Should give it to. Moreover, unless otherwise specified, the compounds described herein may be fully substituted or unsubstituted and the list of compounds includes their derivatives.

  Certain polymerization methods disclosed herein involve contacting a polyolefin monomer with one or more catalyst systems to form a polymer.

Catalyst System The catalyst system used herein can be characterized as a supported catalyst system or an unsupported catalyst system (sometimes referred to as a homogeneous catalyst). Such catalyst systems may be metallocene catalyst systems, Ziegler-Natta catalyst systems or other catalyst systems known to those skilled in the art to be suitable for the production of polyolefins. A brief discussion of such catalyst systems is included below, but is in no way intended to limit the scope of the invention to such catalysts.

A. Ziegler-Natta catalyst system The manufacture of a Ziegler-Natta catalyst system generally involves a metal component (eg, a catalyst precursor) together with one or more additional components, such as a catalyst support, a cocatalyst and / or one or more electron donors. It is done by doing.

Specific examples of catalyst precursors generally have the formula:
MR _x
[Wherein M is a transition metal, R is a halogen, alkoxy or hydrocarboxyl group, and x is the valence of the transition metal]
It is a metal component represented by these. For example, x may be 1 to 4. The transition metals of such Ziegler-Natta catalyst compounds can be selected from groups IV to VIB in one embodiment, and in more particular embodiments titanium, as described throughout the specification and claims. , Chromium or vanadium can be selected. R, in one embodiment, can be selected from chlorine, bromine, carbonate, ester or alkoxy groups. Examples of catalyst precursors include, but are not limited to, TiCl ₄ , TiBr ₄ , Ti (OC ₂ H ₅ ) ₃ Cl, Ti (OC ₃ H ₇ ) ₂ Cl ₂ , Ti (OC ₆ H ₁₃ ). ₂ Cl ₂ , Ti (OC ₂ H ₅ ) ₂ Br ₂ and Ti (OC ₁₂ H ₂₅ ) Cl ₃ are included.

One skilled in the art will recognize that the catalyst precursor has been "activated" in several ways so that it is useful for promoting the polymerization catalyst. As discussed further below, activation can be achieved by combining the catalyst precursor with an activator (also sometimes referred to as a “cocatalyst”). The term “ZN activator” as used herein refers to either a supported or unsupported compound or combination of compounds that can activate a ZN catalyst precursor. Specific examples of such activators include, but are not limited to, organoaluminum compounds such as trimethylaluminum (TMA), triethylaluminum (TEAl) and triisobutylaluminum (TiBAl).

  Such Ziegler-Natta catalyst systems may further contain one or more electron donors that improve stereoselectivity, such as internal electron donors and / or external electron donors. Use of an internal electron donor can reduce the amount of xylene solubles contained in the polymer by reducing the degree of atactic form exhibited by the resulting polymer. A polymer is “atactic” (low stereoselectivity) when pendant groups are arranged in a random manner on either side of the polymer chain. In contrast, a polymer when all of the pendant groups are arranged on the same side of the chain is “isotactic” and the weight when the pendant groups are alternating on opposite sides of the chain. The coalescence is “Syndiotactic” (both are examples of high stereoselectivity). Such internal electron donors can in one embodiment include amines, amides, esters, ketones, nitriles, ethers and phosphines. Internal electron donors in more specific embodiments include, but are not limited to, diethers, succinates and phthalates such as US Pat. No. 5,945,366, which is hereby incorporated by reference. Those described in. In another embodiment, internal electron donors include dialkoxybenzenes such as those described in US Pat. No. 6,399,837, which is incorporated herein by reference.

  Using an external electron donor can further limit the amount of atactic polymer produced. Such external electron donors can include mono- or polyfunctional carboxylic acids, carboxylic anhydrides, carboxylic esters, ketones, ethers, alcohols, lactones, organophosphorus compounds and / or organosilicon compounds. External donors in one embodiment can include diphenyldimethoxysilane (DPMS), cyclohexylmethyldimethoxysilane (CDMS), diisopropyldimethoxysilane and / or dicyclopentyldimethoxysilane (CPDS). The external donor may be the same or different from the internal electron donor used.

  Components of such Ziegler-Natta catalyst system (eg, catalyst precursor, activator and / or electron donor) may be associated with the support in combination with each other or in separate forms with each other, or It does not have to be related. Typical carrier materials can include magnesium dihalides, such as magnesium dichloride or magnesium dibromide.

  Ziegler-Natta catalyst systems and methods suitable for producing such catalyst systems are at least US Pat. No. 4,298,718, US Pat. No. 4,544,717 and US Pat. No. 4,767,735 ( Which are incorporated herein by reference).

B. Metallocene Catalyst Systems Metallocene catalysts are generally cyclopentadienyl (Cp) groups coordinated to transition metals by π bonds (which may be substituted or unsubstituted, each substituent being the same or different May be characterized as a coordination compound incorporating one or more.

The Cp substituent may be a straight chain, branched or cyclic hydrocarbyl group. The cyclic hydrocarbyl group may further form other adjacent ring structures, such as, for example, indenyl, azulenyl and fluorenyl groups. Such additional ring structures may also be substituted or unsubstituted with hydrocarbyl groups such as C ₁ to C ₂₀ hydrocarbyl groups.

A specific example of a metallocene catalyst is a metallocene compound having a bulky ligand, which generally has the formula:
[L] _m M [A] _n
[Wherein L is a bulky ligand, A is a leaving group, M is a transition metal, and m and n are such that the total valence of the ligand corresponds to the valence of the transition metal. It is a number to do]
It is represented by For example, m may be 1 to 3 and n may be 1 to 3.

  The metal atom “M” of such metallocene catalyst compounds can be selected from group 3 to group 12 atoms and lanthanide group atoms in one embodiment, as described throughout the specification and claims. Yes, in a more specific embodiment, it is possible to select from Group 3 to Group 10 atoms, and in an even more specific embodiment, Sc, Ti, Zr, Hf, V, Nb, Ta, Mn, Re, Fe, Ru, Os, Can be selected from Co, Rh, Ir and Ni, and in a more particular embodiment can be selected from Group 4, 5 and 6 atoms, and in a still more specific embodiment can be selected from Ti, Zr, Hf atoms In yet a more particular embodiment, it can be Zr. The oxidation state of the metal atom “M” may range from 0 to +7 in one embodiment, is +1, +2, +3, +4 or +5 in a more particular embodiment, and is +2 in an even more particular embodiment. , +3 or +4. The group attached to the metal atom “M” is such that the compounds represented by the following formulas and structures are electrically neutral unless otherwise specified.

  Bulky ligands generally include cyclopentadienyl groups (Cp) and derivatives thereof. One or more Cp ligands form at least one chemical bond with the metal atom M to form a “metallocene catalyst compound”. The Cp ligand is different from the leaving group bonded to the catalyst compound in that it does not cause much substitution / extraction reaction.

Cp typically contains one or more fused rings or a ring system. Such one or more rings or one or more ring systems are typically group 13 to 16 atoms such as carbon, nitrogen, oxygen, silicon, sulfur, phosphorus, germanium, boron, aluminum and It contains atoms selected from these combinations, and carbon constitutes at least 50% of the ring members. Non-limiting examples include 2-methyl, 4-phenylindenyl; cyclopentadienyl; cyclopentaphenanthreneyl; indenyl; benzoindenyl; fluorenyl; tetrahydroindenyl; octahydrofluorenyl; cyclooctatetraenyl; Cyclopentacyclododecene; phenanthroindenyl; 3,4-benzofluorenyl; 9-phenylfluorenyl; 8-H-cyclopent [a] acenaphthylenyl; 7-H-dibenzofluorenyl; , 2-9] anthrene; thiophenoindenyl; thiophenofluorenyl; their hydrogenated variants (eg 4,5,6,7-tetrahydroindenyl or H ₄ Ind), their substituted variants and heterocyclic Variations are included.

  Cp substituents include hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, aryl, acyl, aroyl, alkoxy, aryloxy, alkylthio, dialkylamine, alkylamide, alkoxycarbonyl, aryloxycarbonyl, carbamoyl, alkyl- and Dialkyl-carbamoyl, acyloxy, acylamino, aroylamino and combinations thereof may be included. More specific non-limiting examples of alkyl substituents include methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopentyl, cyclohexyl, benzyl, phenyl, methylphenyl and t-butylphenyl groups, and so on. Isomers such as t-butyl, isopropyl and the like are included. Other possible groups include substituted alkyl and aryl such as fluoromethyl, fluoroethyl, difluoroethyl, iodopropyl, bromohexyl, chlorobenzyl and the like, and organic metalloid groups substituted with hydrocarbyl (trimethylsilyl, Organic trimetallic groups substituted with halocarbyl [including tris (trifluoromethyl) silyl, methylbis (difluoromethyl) silyl, bromomethyldimethylgermyl, etc.], disubstituted Boron group (including dimethylboron etc.), disubstituted group 15 group (including dimethylamine, dimethylphosphine, diphenylamine, methylphenylphosphine) and group 16 group (methoxy, ethoxy, propoxy, phenoxy, methylsulfide) Include ethyl sulfide and) are included. Other substituents R include olefins such as, but not limited to, olefinically unsaturated substituents (including vinyl terminal ligands such as 3-butenyl, 2-propenyl, 5-hexenyl, etc.) It is. In one embodiment, at least two R groups, and in one embodiment two adjacent R groups are taken together to form carbon, nitrogen, oxygen, phosphorus, silicon, germanium, aluminum, boron, and these A ring structure having 3 to 30 atoms selected from the combination is formed. Further, the substituent R group, such as 1-butanyl, may form a bonding relationship with the element M.

Each anionic leaving group is independently halogen ion, hydride, C ₁ to C ₁₂ alkyl, C ₂ to C ₁₂ alkenyl, C ₆ to C ₁₂ aryl, C ₇ to C ₂₀ alkyl aryl, C ₁ to C ₁₂ Alkoxy, C ₆ to C ₁₆ aryloxy, C ₇ to C ₁₈ alkyl aryloxy, C ₁ to C ₁₂ fluoroalkyl, C ₆ to C ₁₂ fluoroaryl, C ₁ to C ₁₂ heteroatom-containing hydrocarbon and substituted derivatives thereof In yet more specific embodiments, hydrides, halogen ions, C ₁ to C ₆ alkyl carboxylates, C ₁ to C ₆ fluorine substituted alkyl carboxylates, C ₆ to C ₁₂ aryl carboxylates, C ₇ to C ₁₈ alkyl aryl carboxylates C ₁ to C ₆ fluoroalkyl, C ₂ to C ₆ fluoroalkenyl and C ₇ to C ₁₈ fluoroalkylaryl, in an even more specific embodiment hydride, chloride, fluoride, methyl, phenyl, phenoxy, benzoxy, tosyl, fluoromethyl and fluorophenyl, and in an even more specific embodiment C ₁ to C ₁₂ alkyl, C ₂ to C ₁₂ alkenyl, C ₆ to C ₁₂ aryl, C ₇ to C ₂₀ alkyl aryl, substituted C ₁ to C ₁₂ alkyl, substituted C ₆ to C ₁₂ aryl, substituted C ₇ to C ₂₀ alkylaryls, C ₁ to C ₁₂ heteroatom containing alkyls, C ₁ to C ₁₂ heteroatom containing aryls and C ₁ to C ₁₂ heteroatom containing alkyl aryls, and in a more particular aspect chloride, fluoride, C ₁ to C ₆ alkyl, from _{C 2 6} alkenyl, _{C 18} alkylaryl from _{C 7,} halogen-substituted _{C 1 C 6} to alkyl, _{C 18} alkylaryl halogen-substituted _{C 2} from _{C 6} alkenyl and halogen substituted _{C 7,} an even more particular embodiment fluoride, methyl, ethyl Propyl, phenyl, methylphenyl, dimethylphenyl, trimethylphenyl, fluoromethyl (mono-, di- and trifluoromethyl) and fluorophenyl (mono-, di-, tri-, tetra- and pentafluorophenyl), and more In a particular embodiment, it is selected from any leaving group such as fluoride and each of the anionic leaving groups can include any of them.

Other non-limiting examples of leaving groups include amines, phosphines, ethers, carboxylates, dienes, hydrocarbon groups having 1 to 20 carbon atoms, fluorine-substituted hydrocarbon groups [eg -C ₆ F ₅ (pentafluoro Phenyl)], fluorine-substituted alkylcarboxylates [eg CF ₃ C (O) O ⁻ ], hydrides, halogen ions and combinations thereof. Other examples of leaving groups include alkyl groups such as cyclobutyl, cyclohexyl, methyl, heptyl, tolyl, trifluoromethyl, tetramethylene, pentamethylene, methylidene, methoxy, ethioxy, propoxy, phenoxy, bis (N-methylanilide). ), Dimethylamide, dimethylphosphide groups and the like. In one embodiment, two or more leaving groups form part of a fused ring or ring system.

L and A may be bridged with each other. Bridged metallocenes are for example represented by the general formula:
XCp ^A Cp ^B MA _n
[Wherein X is a structural bridge, Cp ^A and Cp ^B each represent a cyclopentadienyl group and each may be the same or different and may be substituted or unsubstituted, M is a transition metal, and A is an alkyl, hydrocarbyl or halogen group, and n is an integer from 0 to 4, in a particular embodiment, either 1 or 2.]
Etc. can be described.

Non-limiting examples of bridging groups (X) include at least one group 13 to 16 atom, such as, but not limited to, carbon, oxygen, nitrogen, silicon, aluminum, boron, germanium, tin and these A divalent hydrocarbon group containing at least one of the combinations, and such heteroatoms are also substituted with a C ₁ to C ₁₂ alkyl substituted to satisfy the neutrality of the valence or It may be aryl. Such bridging groups may also contain substituents as defined above, and such substituents include halogen groups and iron. More specific non-limiting examples of bridging groups are C ₁ to C ₆ alkylene, substituted C ₁ to C ₆ alkylene, oxygen, sulfur, R ₂ C═, R ₂ Si═, —Si (R) ₂ Si (R ₂ ). -And R ₂ Ge =, RP = (where “=” represents two chemical bonds), where R is independently hydride, hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, hydrocarbyl substitution. Selected from the group consisting of organic semimetals, halocarbyl substituted organic metalloids, disubstituted boron, disubstituted group 15 atoms, substituted group 16 atoms and halogen groups, and two or more R together form a ring or ring system You may do it. The bridged metallocene catalyst component in one embodiment has two or more bridging groups (X).

  As used herein, the term “metallocene activator” is either a supported or unsupported compound or combination of compounds that can activate a single site catalyst compound (eg, a metallocene, a Group 15-containing catalyst, etc.). Define. It typically involves withdrawing at least one leaving group (eg, the A group in the above formula / structure) from the metal center of the catalyst component. Thus, the catalyst component of the present invention is activated using such an activator in the direction in which it causes olefin polymerization. Examples of such activators include Lewis acids such as cyclic or oligomeric polyhydrocarbyl aluminum oxides and so-called non-coordinating ionic activators (“NCAs”), or “ionizing activators” or Also included are "stoichiometric activators" or any other compound that has the ability to convert a neutral metallocene catalyst component to an active metallocene cation for olefin polymerization.

  More particularly, activating the required metallocene described herein using a Lewis acid such as an alumoxane (eg “MAO”), a modified alumoxane (eg “TIBAO”) and an alkylaluminum compound as an activator. Is within the scope of the present invention. Other activators based on MAO and aluminum are well known in the art. Non-limiting examples of aluminum alkyl compounds that can be used as activators for the catalysts described herein include trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, and the like. Is included.

Ionization activators are well known in the art and are described in, for example, Eugene You-Xian Chen and Tobin J. et al. Marks, Cocatalysts for Metal-Catalyzed Olefin Polymerization: Activators, Activation Processes, and Structure-Activity Relationships 100 (4) CHEMICAL 13 Examples of neutral ionization activators include group 13 trisubstituted compounds, especially trisubstituted boron, tellurium, aluminum, gallium and indium compounds and mixtures thereof [eg tri (n-butyl) ammonium tetrakis (pentafluorophenyl). ) Boron and / or tris-perfluorophenyl boron metalloid precursors]. Each of these three substituents is independently selected from alkyl, alkenyl, halogen, substituted alkyl, aryl, aryl halide, alkoxy and halide. In one embodiment, the three groups are independently selected from the group of halogen, mono- or polycyclic (including halo substitution) aryl, alkyl, alkenyl compounds, and mixtures thereof. In another embodiment, the three groups are alkenyl groups having 1 to 20 carbon atoms, alkyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, and 3 to 3 carbon atoms. Selected from the group of 20 aryl groups (including substituted aryl) and combinations thereof. In yet another embodiment, the three groups are selected from the group of alkyl having 1 to 4 carbon groups, phenyl, naphthyl, and mixtures thereof. In yet another embodiment, the three groups are highly halogen substituted alkyl of 1 to 4 carbons, highly halogen substituted phenyl, highly halogen substituted naphthyl and mixtures thereof. Select from group. “Highly halogen substituted” means that at least 50% of the hydrogen is replaced by a halogen group selected from fluorine, chlorine and bromine. In yet another embodiment, the neutral stoichiometric activator is a tri-substituted group 13 compound comprising an aryl group that is highly fluorinated, said group being a highly fluorinated phenyl group. It may also be a highly fluorinated naphthyl group.

  Such activators can be combined with a support and the catalyst component (eg, metallocene), such as Gregory G. Hlatky, Heterogeneous Single-Site Catalysts for Olefin Polymerization 100 (4) CHEMICAL REVIEWS 1347-1374 (2000) may be associated with or individually associated with, or associated with, or associated with. You don't have to.

  The metallocene catalyst may be supported or unsupported. Typical support materials may include talc, inorganic oxides, clays and clay minerals, ion exchanged layered compounds, diatomaceous earth compounds, zeolites or resinous support materials such as polyolefins.

Specific inorganic oxides include, but are not limited to, silica, alumina, magnesia, titania and zirconia. The average particle size of the inorganic oxide used as the support material may be from 30 microns to 600 microns or from 30 microns to 100 microns, and the surface area may be from 50 m ² / g to 1,000 m ² / g or 100 m ² / g to 400 m ^2. The pore volume may be from 0.5 cc / g to 3.5 cc / g or from 0.5 cc / g to 2 cc / g. Suitable methods for loading the ionic metallocene catalyst are described in US Pat. Nos. 5,643,847, 09184358 and 09184389, which are hereby incorporated by reference.

Polymerization Method Polyolefin compositions are prepared using a catalyst system, as indicated elsewhere herein. As described above and / or known to those skilled in the art, after the catalyst system is prepared, various steps can be performed with the composition. Various strategies that can be used include, inter alia, the procedure shown in US Pat. No. 5,525,678, which is incorporated herein by reference. The equipment, process conditions, reactants, additives and other materials in a given process will of course vary depending on the desired composition and properties of the resulting polymer. For example, US Pat. No. 6,420,580, US Pat. No. 6,380,328, US Pat. No. 6,359,072, US Pat. No. 6,346,586, US Pat. No. 6,340,730 US Pat. No. 6,339,134, US Pat. No. 6,300,436, US Pat. No. 6,274,684, US Pat. No. 6,271,323, US Pat. No. 6,248,845 , U.S. Patent 6,245,868, U.S. Patent 6,245,705, U.S. Patent 6,242,545, U.S. Patent 6,211,105, U.S. Patent 6,207, The methods shown in US Pat. No. 606, US Pat. No. 6,180,735 and US Pat. No. 6,147,173, which are hereby incorporated by reference, can be used.

  The catalyst system described above can be used over a wide range of temperatures and pressures in a variety of polymerization processes. The temperature may be in the range of about −60 ° C. to about 280 ° C. or about 50 ° C. to about 200 ° C., and the pressure used may be in the range of 1 atmosphere to about 500 atmospheres or more.

  Polymerization methods can include solutions, gas phases, slurry phases, high pressure methods, or combinations thereof.

  In certain embodiments, the method of the present invention comprises one or more olefin monomers having 2 to 30 carbon atoms, 2 to 12 carbon atoms, or 2 to 8 carbon atoms, such as ethylene, propylene, butene, It is directed to solutions such as pentene, methylpentene, hexene, octene and decene, high pressure, slurry or gas phase polymerization processes. Other monomers include ethylenically unsaturated monomers, diolefins having 4 to 18 carbon atoms, conjugated or nonconjugated dienes, polyenes, vinyl monomers and cyclic olefins. Non-limiting monomers can include norbornene, norbornadiene, isobutylene, isoprene, vinyl benzocyclobutane, styrene, alkyl-substituted styrene, ethylidene norbornene, dicyclopentadiene and cyclopentene. In one embodiment, a copolymer such as propylene / ethylene is produced or a terpolymer is produced. Examples of solution methods are US Pat. No. 4,271,060, US Pat. No. 5,001,205, US Pat. No. 5,236,998 and US Pat. No. 5,589,555, which are incorporated by reference. Incorporated herein).

  One example of a gas phase polymerization process generally uses a continuous cycle, in which a circulating gas stream (otherwise known as a recycle stream or fluid medium) is heated with the heat of polymerization in the reaction vessel. . The heat is removed from the recycle stream in another part of the cycle using a cooling device located outside the reactor. A gaseous stream containing one or more monomers may be continuously circulated under reaction conditions through a fluidized bed in which a catalyst is present. The gas stream is removed from the fluidized bed and then recycled back to the reaction vessel. At the same time, after removing the polymer product from the reactor, fresh monomer is added in place of the polymerized monomer [eg US Pat. No. 4,543,399, US Pat. No. 4,588,790. US Pat. No. 5,028,670, US Pat. No. 5,317,036, US Pat. No. 5,352,749, US Pat. No. 5,405,922, US Pat. No. 5,436,304. US Pat. No. 5,456,471, US Pat. No. 5,462,999, US Pat. No. 5,616,661, and US Pat. No. 5,668,228, which are hereby incorporated by reference. See also).

  The reactor pressure in the gas phase process can vary from about 100 psig to about 500 psig, or from about 200 psig to about 400 psig, or from about 250 psig to about 350 psig, and the like. The temperature of the reactor in the gas phase process can vary from about 30 ° C. to about 120 ° C. or from about 60 ° C. to about 115 ° C., from about 70 ° C. to about 110 ° C., or from about 70 ° C. to about 95 ° C. Other gas phase methods contemplated by this method include US Pat. No. 5,627,242, US Pat. No. 5,665,818 and US Pat. No. 5,677,375, which are incorporated herein by reference. Which are described in the specification).

The slurry process generally involves producing a suspension of solid particulate polymer in a liquid polymerization medium, to which a catalyst is added in addition to the monomer and optionally hydrogen. The suspension (which may contain diluent) may be withdrawn intermittently or continuously from the reactor, separating volatile components from the polymer and optionally recirculating to the reactor after distillation. You may let them. The liquefied diluent used in the polymerization medium is typically an alkane having 3 to 7 carbon atoms, such as a branched alkane. The medium used is generally liquid under the polymerization conditions and is relatively inert, such as hexane or isobutane.

  The slurry method or bulk method (for example, a method not using a diluent) can be carried out continuously in one or more loop reactors. The catalyst may be regularly injected into the reactor loop as a slurry or free-flowing dry powder, and the reactor itself is filled with circulating slurry containing the polymer particles growing in the diluent. Also good. In some cases, hydrogen may be added as a molecular weight regulator. The reactor may be maintained at a pressure of about 27 bar to about 45 bar and a temperature of about 38 ° C to about 121 ° C. Since many such reaction vessels are in the form of double jacketed pipes, the heat of reaction may be removed through the loop walls. The slurry is brought out of the reactor at regular intervals or continuously into a heated low pressure flash tank, a tumble dryer and a nitrogen purge column so that the diluent and unreacted monomer and All of the copolymerization monomer is removed in a continuous form. The resulting hydrocarbon free powder may then be made into a compound suitable for use in various applications. Alternatively, other types of slurry polymerization methods may be used, for example, stirring reactors may be positioned in series, in parallel, or a combination thereof.

Polymer Products The polymers produced by the methods described herein can be used in a wide variety of products and end use applications. Such polymers can include polypropylene and polypropylene copolymers.

  In certain embodiments, the methods described herein can be used to produce propylene-based polymers. Such polymers include atactic polypropylene, isotactic polypropylene, semi-isotactic and syndiotactic polypropylene. Other propylene polymers include block or impact resistant propylene copolymers.

  The molecular weight distribution of such a propylene polymer, ie, the weight average molecular weight (Mw / Mn) relative to the number average molecular weight measured by gel permeation chromatography, can be from about 2 to about 20, or from about 2 to about 12.

  In addition, the melt flow rate (MFR) exhibited by such propylene polymers is about 0.5 g / 10 min to about 20.0 g / 10 min or about 1.0 g as measured under ASTM-D-1238-Condition L. / 10 minutes to about 17.0 g / 10 minutes, or about 1.5 g / 10 minutes to about 14.0 g / 10 minutes, or about 1.8 g / 10 minutes to about 10.0 g / 10 minutes.

  Further, the melting point of such a propylene polymer may be at least about 115 ° C. or about 119 ° C. to about 170 ° C. or about 134 ° C. to about 165 ° C. or about 140 ° C. to about 155 ° C. as measured by DSC. .

  The density exhibited by such propylene polymers can be about 0.900 g / cc or about 0.905 g / cc as measured by ASTM D1505.

Product Applications The polymers produced are useful in a variety of end use applications such as film production.

  In one embodiment, such a polymer is used in forming an inflation film. Manufacture of blown films can be performed using any of the methods known to those of ordinary skill in the art, for example, using Davis Standard's 5-layer mini-coextruded blown film line.

  Moreover, such processing can include coextrusion of additional layers to produce a multilayer film. Such additional layers may be co-extruded films known in the art such as syndiotactic polypropylene, low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-propylene copolymer, Any of a butylene-propylene copolymer, an ethylene-butylene copolymer, an ethylene-propylene-butylene terpolymer, an ethylene-vinyl acetate copolymer, an ethylene-vinyl alcohol copolymer, nylon and the like may be used.

  Such a coextruded film or coextruded product has at least an outer layer and a central layer. The outer layer may comprise polypropylene, while the central layer is medium density polyethylene (density 0.927 to 0.947 g / cc or typically 0.937 g / cc) or impact resistant co-polymer. It may contain a polymer. The amount of the impact copolymer contained in the central layer is 15% by weight or less, or the amount of the impact copolymer is 10% by weight or less, or the amount of the impact copolymer is 5% by weight or less. There may be. The center layer comprising the impact copolymer is either polyethylene or another polypropylene, and the amount of the impact copolymer in the center layer is less than 15% by weight based on the total amount of polymer. You may mix so that it may become quantity. The polypropylene may be a polymer produced using a metallocene catalyst or a polymer produced using a Ziegler-Natta catalyst.

  For the purpose of improving or improving the specific properties that the film exhibits in a specific end use, it is possible to include an appropriate additive in an effective amount in one or more of the layers. Such additives may be used during the application stage (formation of blown film) or may be combined with the polymer during the processing stage (pellet extrusion), etc. Such additives include stabilizers (eg, hindered amines, benzofuranones, indolinones) that provide protection against degradation by ultraviolet light, degradation by heat or oxidation and / or degradation by actinic radiation, antistatic agents (eg, medium to high molecular weight (Hydric alcohols and tertiary amines), antiblocks, coefficient of friction modifiers, processing aids, colorants, clarifiers, nucleating agents and other additives known to those skilled in the art. The amount of clearing agent, such as Milliken Millad 3988, may be in the range of 0.15% to 0.3% by weight.

  Polymer-based films in one embodiment include, for example, retail clothing overlaps, specialty bread films, fresh cut product pouches, vertical bag filling and packaging materials for cereals (eg, rice and beans), It is an inflation film that is used in heat-resistant films, sealant webs, frozen food films that reduce the degree of unauthorized use, and used as a minor component in shrink films. Such films generally exhibit resistance to moisture, air and harmful perfume permeation and also exhibit favorable mechanical properties such as strength and transparency.

  The haze value exhibited by such films can be from 1% to about 10% or from 3% to about 9% to about 5% to about 8% as measured by ASTM 1003. The gloss that the film exhibits at a 45 ° angle can be from 50% to about 90%, or from 60% to about 85%, or from about 70% to about 83% as measured by ASTM D523.

  Also, the 1% secant tensile stress (flow direction) exhibited by such films can be from about 80 kpsi to about 200 kpsi or from about 90 kpsi to about 150 kpsi or from about 95 kpsi to about 135 kpsi or from about 96 kpsi to about 120 kpsi as measured by ASTM D882. . Also, the 1% secant tensile stress (lateral direction) exhibited by the film can be from 80 kpsi to about 200 kpsi or from about 90 kpsi to about 150 kpsi or from about 95 kpsi to about 135 kpsi or from about 100 kpsi to about 120 kpsi as measured by ASTM D882.

  Also, the static coefficient of friction exhibited by such films can be less than 1, as measured by ASTM D1894, or from about 0.40 to about 0.85 or from about 0.50 to about 0.60. Also, the dynamic coefficient of friction exhibited by the film is less than 1 as measured by ASTM D1894, or from about 0.35 to about 0.85 or from about 0.50 to about 0.70 or from about 0.52 to about 0.65. It can be.

  Also, the water vapor transmission rate (WVTR) exhibited by such films is from about 0.3 g / 100 square inches / day to about 0.8 g / 100 square inches / day or about 0.4 g / 100 squares as measured by ASTM F1249. Inches / day to about 0.5 g / 100 square inches / day. The film also has an oxygen transmission rate (OTR) of about 100 cc / 100 square inches / day to about 300 cc / 100 square inches / day or about 130 cc / 100 square inches / day to about 200 cc / 100 as measured by ASTM D3985. Square inches / day or about 150 cc / 100 square inches / day to about 180 cc / 100 square inches / day.

  Also, the amount of gel contained in such a film is low, and as a result, the transparency may be higher. Also, the blocking forces exhibited by the film can be from about 5 to about 30, or from about 10 to about 25 or from about 20 to about 24. Also, the seal initiation temperature exhibited by the film can be from about 104 ° C to about 150 ° C or from about 115 ° C to about 140 ° C or from about 120 ° C to about 135 ° C.

  Such films can also exhibit improved hot tack. Hot tack is the strength of a heat seal measured at specified time intervals after the sealing cycle is complete but before the seal reaches ambient temperature. If the seal temperature is too low, the resulting seal is weak and the seal that results when the seal temperature is too high is also weak. The hot tack curve should ideally be in the shape of a bell, which should be suitable for obtaining a high seal strength value where the maximum heat seal strength is possible and the processing window is satisfactory Is shown.

  The degree of Elmendorf tear exhibited by such films is from about 15 grams to about 100 grams or from about 25 grams to about 75 grams or from about 40 grams to about 55 grams in the flow direction as measured by ASTM D-1922 and in the transverse direction. It can be from about 75 grams to about 600 grams or from about 125 grams to about 300 grams or from about 150 grams to about 180 grams.

  The dart impact resistance exhibited by such films can be from about 30 grams to about 90 grams or from about 40 grams to about 75 grams or from about 50 grams to about 70 grams as measured by ASTM D-1709.

Table 1 shows the polypropylene resin used as the skin layer of the resulting coextruded film structure. Resin 1 and Resin 2 are clarified homopolymers using Ziegler-Natta and metallocene, respectively. Resin 3 is a homopolymer using metallocene, resin 4 is a transparent random copolymer using metallocene, and resins 5, 6 and 7 are random copolymers using metallocene.

  A melt index of 0.9 and 0.934 g / cc produced using Tenite 1830F (available from Eastman Voridian), a low density polyethylene (LDPE) with a melt index of 1.7 and 0.92 g / cc, and metallocene. Total Petrochemicals M3410 EP, a medium density polyethylene (mMPE), was used as the resin for the center layer. In one of the film structures, blown film grade Total Petrochemicals 4170 polypropylene, a heterophasic impact copolymer (ICP), was used as a minor component in the central layer.

  Manufacture of such film structures was carried out on a Davis Standard 5-layer co-extruded blown film line. The extruder was a grooved feed, equipped with a 1 inch diameter screw and L / D was 24. The line was characterized by a conical helical mandrel with a die diameter of 60 mm and a die gap of 1.2 mm. The air temperature of the cooling ring was 35 ° C. In addition to the resulting film thickness being 1.2 mil and BUR being 2.5, the structure was an A / B / A type structure with a layer distribution of 25% / 50% / 25%. Table 2 shows the structure of coextruded films produced using the materials described above.

  FIG. 1 shows the gloss values and haze values obtained for the inflation film samples A to E shown in Table 2. The optical properties provided by film sample C were comparable to those of control A (LDPE), but were significantly better than those of control B. The film produced when Resin 2 was used as the skin layer had a haze value of only 3% and a 45 ° gloss of 83%. Even when 15% of ICP was added to the center layer (sample D), the influence on the optical characteristics was negligible. The optical properties provided by Sample E were significantly better than Control B. Table 3 shows the numerical values shown in FIG.

  FIG. 2 shows gloss values and haze values obtained with respect to J from the inflation film samples F shown in Table 2. FIG. 2 also shows the melting points indicated by the skin layer materials used in making these film samples. The optical properties produced by film sample J produced using the random copolymer with the lowest melting point were better than those exhibited by samples F, H and I produced using materials with higher melting points. The optical properties brought about by the film sample G produced using the transparent resin 4 were the best. Table 4 shows the numerical values shown in FIG.

  FIG. 3 shows the flow direction secant tensile stress (rigidity) shown by all of the inflation film samples. The secant tensile stress exhibited by Sample C is five times higher than that of Control A (LDPE), while the optical properties (FIG. 1) are comparable. When 15% of 4170 ICP was added to the center layer (sample D), the secant tensile stress was slightly higher than that of sample C. The secant tensile stress exhibited by the sample produced using the random copolymer resin is lower. The tensile stress produced by film sample J produced using the random copolymer with the lowest melting point was the lowest compared to samples F, H and I produced using materials with higher melting points. Film samples E and G made with the clearing resin had the highest tensile stress. Table 5 shows the numerical values shown in FIG. Table 6 shows the transverse (TD) secant tensile stress (kpsi) and dynamic friction coefficient shown by each sample.

  FIG. 4 shows the Elmendorf tear resistance and dart impact resistance in the flow and transverse directions exhibited by some of the blown film samples. Table 7 shows the values of such data. Table 8 shows average blocking force values. When the polypropylene resin skin was compared with LDPE, the tendency to block was low and the dynamic coefficient of friction value was also relatively low (as shown in Table 6 above). The degree of blocking was lowest for random copolymers, but the dynamic coefficient of friction it showed was higher than that of polypropylene homopolymer.

  While the foregoing is directed to embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, the scope of the invention being determined by the following claims To do.

Claims (16)

A coextruded inflation film having an A / B / A type structure, wherein A is a skin layer and B is a central layer,
The central layer comprises medium density polyethylene or impact copolymer,
The skin layer is a polypropylene having a melt flow rate of from 1.8 g / 10 min to 14.0 g / 10 min and a melting point of at least 115 ° C .;
The blown film has a haze value of less than 10%, a gloss value of 70% or more and a 1% secant tensile stress in the range of 80 kpsi to 150 kpsi;
Inflation film characterized by that . The blown film of claim 1 which also exhibits a 1% secant tensile stress in the range of 80 kpsi to 135 kpsi when the thickness is 1.2 mils .   The blown film according to claim 1, wherein the amount of gel is small.   The blown film according to claim 1, wherein the blown film exhibits a coefficient of friction of less than 1.0.   An inflation film according to claim 1, which exhibits a blocking force of 5 to 25.   The blown film according to claim 1, which exhibits a sealing start temperature of 104 ° C to 150 ° C.   The blown film of claim 1, wherein the blown film exhibits a WVTR of 0.3 to 0.8 g / 100 square inches / day.   2. A blown film according to claim 1, which exhibits an OTR of 100 to 300 cc / 100 square inches / day. Blown film according to claim 1 wherein the amount of impact copolymers where the center layer contains is 15 wt% or less.   The blown film according to claim 1, wherein the polypropylene is produced using a metallocene catalyst.   The inflation film according to claim 1, wherein the polypropylene is produced using a Ziegler-Natta catalyst. The inflation film according to claim 11, further comprising a clarifying agent. 13. A blown film according to claim 12, wherein the clarifier is present in an amount of 0.15% to 0.3% by weight.  A product comprising the blown film according to claim 1. Whether it is an overlap for retail clothing, a film for special bread, a pouch for fresh cut products, a vertical bag filling and packaging material for cereals , a heat-resistant film, a sealant web, or a frozen food film that reduces the degree of unauthorized use 15. A product as claimed in claim 14 as a minor component in a shrink film. A method of forming an inflation film,
Ziegler-Natta catalyst prepared polypropylene showing a melt flow rate and at 115 ° C. The melting point of the 1.8 g / 10 min to 14.0 g / 10 min was produced using,
A skin layer of a coextruded blown film having an A / B / A type structure, wherein A is a skin layer and B is a central layer containing medium density polyethylene or an impact-resistant copolymer Consisting of forming,
The blown film has a haze value of less than 10%, a gloss value of 70% or more and a 1% secant tensile stress (flow direction) in the range of 80 kpsi to 150 kpsi;
The method comprises quenching the inflation film with air having a temperature of less than 10 ° C. and further comprising internal bubble cooling, external bubble stabilization and dual lip air rings.
A method characterized by that.

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